Nursing mothers frequently use mechanized pumps to express milk from their breasts for bottle-feeding their infant children. Some such pumps are manually operated, in that the pumping action is motivated by reciprocating a piston or lever by hand, or compressing a flexible bulb. Often the pump lever is located directly on a structure that must be held against the breast while the lever is reciprocated. Other such pumps are electrically operated, and are generally considered less fatiguing than manual pumps. Between uses, careful cleaning is required to keep the pump components that come in contact with breast milk sanitary.
Pumped milk must typically be refrigerated if it will not be immediately consumed. It is common to store such milk in sanitized bottles or bags. Improvements to pump constructions and pumping methods are desired, for comfortable and sanitary use.